A growing number of Asian cities are experiencing a rapid rise in the numbers of motorized twowheelers. In many of those cities, these vehicles account for the majority of traffic. This has significant ramifications, both positive and negative, for road safety, congestion, air pollution, economic development, and climate change.

This study is a comprehensive review of the best practices in regulation and design of two-and-three-wheelers in urban traffic. While it mostly concentrates on the motorized two-and-three-wheelers in Asian cities, the review treats this mode of transportation as only one among many. It recognizes that even tightly targeted measures will affect other modes, most directly pedestrians and non-motorized two-and-three-wheelers. Therefore, in the spirit of promoting the conception of complete streets and livable cities, the review treats street and road space as a whole, discusses motorized two-and-three-wheelers in relation to other modes, and touches upon issues relevant to other modes but analogous to those of two-and three-wheelers.